1. Field of the Invention
The present invention relates to a current lead-in conductor for an illumination lamp with a glass base, which conductor is made of metal.
2. Description of the Prior Art
Illumination lamps include incandescent lamps, gas discharge lamps, flash lamps and the like. An illumination lamp has a hollow glass body and a substantially massive or solid glass base connected with the hollow glass body. The current lead-in conductor is partially fused into the glass base and partially projects outwardly from the base. The current lead-in conductor is a heavy solid body made of an appropriate alloy. The known current lead-in conductors for the illumination lamps are made of an alloy consisting of 98% Ni by weight and 2% Mn by weight. Nickel is a rather expensive metal and, of course, it is desirable to be able to make the current lead-in conductors of a cheaper material. However, the current lead-in conductors should meet certain requirements which the desired cheap materials (substitute metals) should satisfy. These requirements are:
The use of a substitute metal should not make the production of the current lead-in conductors more difficult.
The substitute metal should, during fusing-in of the conductor into the glass base, withstand the fusing temperatures of about 1,200.degree. C.
The substitute metal should have a good electrical conductance to insure current supply into the interior of the illumination lamp.
The substitute metal should have a good heat conductance to be able to carry away heat from the lamp interior.
The substitute metal should be able to withstand operational temperatures of 150-200.degree. C. which prevail at the outwardly projecting portion of the current lead-in conductor.
The substitute metal should have a very good corrosion resistance in the presence of oxygen and heat.
Accordingly, an object of the present invention is to provide a relatively cheap metallic material for making the current lead-in conductors which would meet all of the above-listed requirements.